1. Field of the Invention
The present invention relates to a silicon carbide semiconductor device and a method for manufacturing the same, and more particularly to a silicon carbide semiconductor device having a silicon carbide layer with a trench formed therein and a method for manufacturing the same.
2. Description of the Background Art
Japanese Patent Laying-Open No. 2009-188221 discloses a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) having a silicon carbide substrate with a trench formed therein. The publication also discloses that it is necessary to control an angle of a side wall of the trench to a specific angle in order to obtain a MOSFET having high channel mobility.
However, when the angle of the side wall of the trench is determined from the viewpoint of channel mobility, it has sometimes been difficult to perform the step of filling a gate electrode into the trench due to a high aspect ratio of the trench.